Liquid dispensers, such as liquid soap and sanitizer dispensers, provide a user with a predetermined amount of liquid upon the actuation of the dispenser. It is known to dispense liquids, such as soaps, sanitizers, cleansers and disinfectants, from a dispenser housing that uses a removable and replaceable cartridge containing the liquid. The pump mechanisms employed with such dispensers are typically liquid pumps that dispense a predetermined quantity of the liquid upon movement of an actuator. Accordingly, if a company offers several different products that require different quantities of liquid to be dispensed, the company must make, stock and handle several different liquid pumps. In addition, it is sometimes desirable to dispense the liquids in the form of foam by, for example, interjecting air into the liquid creating a foamy mixture of liquid and air bubbles. Again, different products may require different volumes of liquid and air to be dispensed. Accordingly, if the company also sells several types of foam dispensing products, the company may also have to make, stock and handle several different foam pumps.